1. Technical Field
The present application relates to a method for filling bottles or similar containers with an oxygen sensitive effervescent liquid beverage filling material under counterpressure and filling machine for the performance of this method.
2. Background Information
Background information is for informational purposes only and does not necessarily admit that subsequently mentioned information and publications are prior art.
The present application relates to a method for filling bottles or similar containers with a liquid under counterpressure, using a filling machine which has, on a rotor, a plurality of filling elements, a bowl that is common to the filling elements, whereby the interior of the bowl forms a liquid space which is occupied by the liquid being bottled and a headspace above the liquid for an inert gas under pressure (filling pressure), and at least one return gas duct which is common to the filling elements or to each of a group of filling elements, whereby before the filling, the interior of the container is pressurized by means of a controlled gas path of each filling element with inert gas originating from the headspace of the bowl and at the filling pressure, and during the filling at least some of the inert gas is displaced from the containers by the incoming liquid into the at least one return gas duct. The present application also relates to a filling machine with a rotary construction for the filling of bottles or similar containers with a liquid under counterpressure, with a bowl which is provided on a rotor that can be driven in rotation around a vertical machine axis, whereby the interior of the bowl forms a liquid space which is occupied by the liquid being bottled and a headspace above the surface of the liquid being bottled for an inert gas under pressure (filling pressure), with a plurality of filling elements located on the periphery of the rotor, each of which has a fluid duct which is in communication with the liquid space of the bowl and a discharge opening with a controlled liquid valve, with at least one common return gas duct on the rotor which is common to the filling elements or a group of filling elements, and with controlled gas paths realized in the filling elements, by means of which gas paths the individual container to be filled and located in sealed contact with a filling element can be pressurized with an inert gas at the filling pressure from the headspace of the bowl, and which makes possible a removal of the inert gas displaced from the containers during the filling at least partly to the return gas duct.
The filling of bottles or similar containers may include filling with a liquid, in one possible embodiment with a carbonated liquid such as beer, for example, with the use of counterpressure with a single-chamber filling system. In such processes, the liquid being bottled is prepared in a bowl which is common to a plurality of filling elements of a filling machine that employs a rotary construction, whereby the interior of the bowl is divided into a liquid chamber which is occupied by the liquid being bottled and a headspace which is located above it and is filled with an inert gas. The inert gas is thereby generally carbon dioxide or carbon dioxide gas. The entire bowl and its contents are thereby under bottling pressure.
Before the actual filling, each container located in sealed contact with the filling element is pressurized to the filling pressure with inert gas. The pressurization gas used for this purpose is at least partly the inert gas that is housed in the bowl and is extracted from the bowl for the purpose. During the filling, some of the pressurization or inert gas which is displaced from the respective container by the incoming liquid is returned into a rotor-side return gas duct which is common to the filling elements of the filling machine, but some of the gas is also returned to the headspace of the bowl, for economic reasons among other things, i.e. to reduce the consumption of inert gas.
To increase the shelf life and quality of the liquid being bottled, the interior of the containers that are in sealed contact with the filling elements can be flushed with inert gas one or more times before the pressurization, whereby the container is evacuated before and/or after each purging, and in one possible embodiment by a controlled connection of the interior of the individual bottle with a rotor-side vacuum duct which is common to the filling elements.
In spite of the evacuation and purging, however, a small amount of air or oxygen remains in the pressurized containers, so that during the filling not only is inert gas or carbon dioxide gas returned into the headspace of the bowl, but a certain amount of air and/or oxygen is returned along with it. As a result, the liquid being bottled begins to absorb oxygen while it is still in the bowl, and in one possible embodiment at the boundary surface between the liquid being bottled and the inert gas/oxygen mixture above it, which has an adverse effect on the shelf life and quality of the liquid being bottled.